Iron / carbon multilayer film, electrode material, battery and method

Abstract

Embodiments of the present application disclose an iron / carbon multilayer film, an electrode material, a battery and a method. The iron / carbon multilayer film includes an iron thin film and a carbon thin film, and the iron thin film and the carbon thin film are alternately arranged. The iron / carbon multilayer film provided by the embodiments of the present application stores energy based on the spin capacitance effect of space charge storage, and has a high energy density, good rate performance and good cycle stability.

Description

Technical Field

[0001] The present application relates to the technical field of battery materials, and in particular to an iron / carbon multilayer film, an electrode material, a battery and a method. Background Art

[0002] Ion battery is a new type of efficient chemical power source with the advantages of high energy density, long cycle life, high operating voltage, no memory effect, low self-discharge and wide operating temperature range. It is an ideal chemical power source for various portable electronic products today and the preferred power source for electric vehicles in the future. It has broad application space and economic value.

[0003] Ion batteries are usually composed of positive electrodes, negative electrodes and electrolytes. Among them, the electrode material is one of the key materials of lithium-ion batteries, and its performance directly determines the performance of ion batteries.

[0004] Therefore, how to design electrode materials with better performance is a technical problem that needs to be solved urgently in this field. Summary of the invention

[0005] The embodiments of the present application provide an iron / carbon multilayer film, an electrode material, a battery and a method to help solve the problem of poor performance of electrode materials in the prior art.

[0006] In a first aspect, an embodiment of the present application provides an iron / carbon multilayer film, comprising:

[0007] The iron film and the carbon film are arranged alternately.

[0008] Preferably, the thickness of the carbon film is greater than the thickness of the iron film.

[0009] Preferably, the thickness of the carbon film is 2.5-3.5 nm, and the thickness of the iron film is 0.5-1.5 nm.

[0010] Preferably, the number of layers of the iron film is greater than or equal to 1 layer, and the number of layers of the carbon film is greater than or equal to 1 layer.

[0011] Preferably, the multilayer film performs energy storage based on space charge.

[0012] Preferably, the multilayer film is used for magnetic regulation.

[0013] In a second aspect, the present application provides a method for preparing an iron / carbon multilayer film, comprising:

[0014] The magnetron sputtering method is adopted to alternately grow iron thin films and carbon thin films to obtain the transition metal / carbon multilayer film described in any one of the first aspects.

[0015] In a third aspect, an embodiment of the present application provides an electrode material, including the iron / carbon multilayer film described in any one of the first aspects.

[0016] In a fourth aspect, an embodiment of the present application provides an ion battery, including the electrode material described in the third aspect.

[0017] The iron / carbon multilayer film provided by the embodiment of the present application stores energy based on the spin capacitance effect of space charge storage, and has high energy density, good rate performance and good cycle stability.

[0018] In addition, the magnetron sputtering method can be used to prepare the multilayer film to precisely control the interface and maximize the interface content, which is beneficial to the preparation of high-capacity energy storage devices. Description of the Drawings

[0019] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, for those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0020] Figure 1 It is the magnetization curve of a transition metal / titanium dioxide multilayer film material provided by an embodiment of the present application under a magnetic field of 3T;

[0021] Figure 2 It is the charge-discharge curve of an ion battery provided by an embodiment of the present application;

[0022] Figure 3 It is the long cycle curve of an ion battery provided by an embodiment of the present application;

[0023] Figure 4 It is the curve of magnetization intensity changing with the charge and discharge of the battery provided by an embodiment of the present application. Detailed Embodiments

[0024] In order to enable those skilled in the art to better understand the technical solutions in the present application, the following will clearly and completely describe the technical solutions in the embodiments of the present application with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present application.

[0025] The space charge effect stems from the tendency of charge separation between ions and electrons at the heterogeneous interface of ionic conductors / electronic conductors. This effect is the source of the extra capacity of metal compound and alloy electrode materials in energy storage devices. Storing charges through ferromagnetic metal interfaces leads to changes in magnetism, enabling effective cross-application in the two major fields of electrochemistry and magnetism, such as the design of new high-efficiency energy storage devices, information writing, reading, and storage, and the development of spintronic devices. Energy storage dominated by the space charge mechanism has advantages such as high energy density, high power density, long cycle life, and good rate performance. In addition, under the action of an electric field, the accumulation / release of ions at the surface of ferromagnetic metals effectively affects the number and arrangement of spin electrons at the Fermi level of the 3d orbit, and thus the purpose of magnetic regulation can be achieved. This regulation method has advantages such as fast response speed, low energy consumption, non-volatility, stable reversibility, and long life, and has great application value in new spintronic devices and information storage devices.

[0026] Based on this principle, the embodiments of the present application provide an iron / carbon multilayer film, which can store energy based on space charge, and has high energy density, good rate performance, and good cycle stability.

[0027] Specifically, the iron / carbon multilayer film provided by the embodiments of the present application includes iron thin films and carbon thin films, and the iron thin films and the carbon thin films are arranged alternately.

[0028] In an alternative embodiment, the thickness of the carbon thin film is greater than the thickness of the iron thin film.

[0029] In an alternative embodiment, the thickness of the carbon thin film is 2.5 - 3.5 nm, and the thickness of the iron thin film is 0.5 - 1.5 nm.

[0030] It should be noted that the embodiments of the present application do not limit the number of layers of the iron / carbon multilayer film. Those skilled in the art can set the iron thin films and / or carbon thin films to appropriate numbers of layers according to actual needs. It is understandable that both the iron thin films and the carbon thin films should be greater than or equal to 1 layer. In some possible implementation manners, the iron thin films and the carbon thin films are respectively set to 40 layers, 50 layers, 60 layers, or 70 layers. Of course, other numbers of layers are also possible, and will not be enumerated here.

[0031] Corresponding to the above iron / carbon multilayer film, the embodiments of the present application also provide a preparation method of the iron / carbon multilayer film. Specifically, magnetron sputtering can be used to alternately grow iron thin films and carbon thin films to obtain the iron / carbon multilayer film. During the magnetron sputtering process, the thickness and number of layers of the iron thin films and the carbon thin films can be controlled to obtain the iron / carbon multilayer film that meets the requirements.

[0032] In some possible implementation manners, [Fe(1nm) / C(3nm)] is prepared by magnetron sputtering 40Thin film materials. Among them, the thickness of the Fe thin film is 1 nm; the thickness of the C thin film is 3 nm. The number of layers of the Fe thin film and the C thin film are 40 layers respectively.

[0033] Specifically, a 2-inch Fe target with a thickness of 0.3 mm and a purity of 99.99% and a 2-inch C target with a thickness of 0.3 mm and a purity of 99.99% are alternately sputtered onto a copper foil substrate to prepare [Fe(1 nm) / C(3 nm)] 40 thin film materials.

[0034] Among them, the best optimization conditions for growth at room temperature are: the deposition pressure is 7.5 mTorr, the flow rate is 30 sccm, and the DC sputtering powers are 30 W for Fe and 100 W for C respectively; the rotation speed of the sample stage is maintained at 5 rad / min during the growth process; the target-substrate distance is 8 cm. The thickness of each layer of Fe deposition is 1 nm, the thickness of each layer of C deposition is 3 nm, and Fe and C are each deposited 40 layers.

[0035] Corresponding to the above iron / carbon multilayer film, an embodiment of the present application also provides an electrode material, which includes the above iron / carbon multilayer film.

[0036] Corresponding to the above electrode material, an embodiment of the present application also provides an ion battery, which includes the above electrode material.

[0037] The ion battery provided by the embodiment of the present application can perform reversible charging / discharging within a suitable potential range, and utilize the space charge region on the Fe surface to realize the separate storage and release of electrons and ions, so as to achieve the purpose of storing energy. The range of this potential range can be obtained through experiments or other means, and the embodiment of the present application does not limit this.

[0038] It should be noted that this energy storage mechanism is different from the past traditional electrode materials based on embedding, conversion, and alloying energy storage methods. During this energy storage method, a space charge region can be formed on the iron surface, that is, electrons can continue to be stored in the 3d split orbitals at the Fermi level. Correspondingly, ions can be adsorbed on the iron surface. This storage mechanism is a new discovery and is applied in the energy storage field for the first time. This energy storage method is actually a surface charge storage with capacitive behavior and can still have a high capacity retention rate at a large current density.

[0039] In addition, under the action of an electric field, the charge accumulation / release on the iron surface effectively affects the arrangement of spin charges at the Fermi level of the 3d orbit, and thus the purpose of magnetic regulation can be achieved. Therefore, the iron / carbon multilayer film provided by the embodiment of the present application can also be used for magnetic regulation. This regulation method has the advantages of fast response speed, low energy consumption, non-volatility, stable reversibility, and long life.

[0040] SeeFigure 1 , which is the magnetization curve of an iron / carbon multilayer film material provided by an embodiment of the present application under a magnetic field of 30000 Oe. Among them, the iron / carbon multilayer film material is [Fe(1nm) / C(3nm)] 40 material. The test result of the magnetization curve of the iron / carbon multilayer film material shows superparamagnetic characteristics, reflecting that the iron particles have nanoscale dimensions, thus having a large specific surface area, which can adsorb more ions and achieve a higher energy density.

[0041] See Figure 2 , which is the charge-discharge curve of an ion battery provided by an embodiment of the present application. The ion battery can be a lithium-ion battery, and the electrode material of the lithium-ion battery is [Fe(1nm) / C(3nm)] 40 material.

[0042] See Figure 3 , which is the long cycle curve of an ion battery provided by an embodiment of the present application. Among them, the ion battery can be a lithium-ion battery, and the electrode material of the lithium-ion battery is [Fe(1nm) / C(3nm)] 40 material.

[0043] See Figure 4 , which is the curve of the magnetization intensity changing with the charge and discharge of an ion battery provided by an embodiment of the present application. Among them, the ion battery can be a lithium-ion battery, and the electrode material of the lithium-ion battery is [Fe(1nm) / C(3nm)] 40 material.

[0044] The iron / carbon multilayer film material provided by the embodiment of the present application stores energy based on the spin capacitance effect of space charge storage, and has high energy density, good rate performance and good cycle stability when applied to ion batteries.

[0045] It should be noted that in this article, relational terms such as "first" and "second" are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the term "comprising", "including" or any other variant thereof is intended to cover non-exclusive inclusion, so that a process, method, article or device comprising a series of elements not only includes those elements, but also includes other elements not expressly listed, or also includes elements inherent to such process, method, article or device. Without further limitation, an element defined by the statement "comprising one..." does not exclude the presence of additional identical elements in the process, method, article or device comprising the element.

[0046] The above are only specific embodiments of the present invention, enabling those skilled in the art to understand or implement the present invention. Various modifications to these embodiments will be obvious to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to these embodiments shown herein, but rather to the broadest scope consistent with the principles and novel features disclosed herein.

[0047] In this specification, the same or similar parts among various embodiments can be referred to each other. In particular, for the terminal embodiments, since they are basically similar to the method embodiments, they are described relatively simply, and the relevant parts can be referred to the descriptions in the method embodiments.

[0048] The above-described embodiments of the present application do not constitute a limitation on the protection scope of the present application.

Claims

1. A kind of iron / carbon multilayer film, characterized in that, Applied to the electrode material of an ion battery, the iron / carbon multilayer film comprises: An iron thin film and a carbon thin film, with the iron thin film and the carbon thin film arranged alternately; The iron / carbon multilayer film is used for energy storage based on the spin capacitance effect of space charge storage, or for magnetic regulation; The thickness of the carbon thin film is greater than that of the iron thin film; The thickness of the carbon thin film is 2.5 - 3.5 nm, and the thickness of the iron thin film is 0.5 - 1.5 nm; The number of layers of the iron thin film is greater than or equal to 1 layer, and the number of layers of the carbon thin film is greater than or equal to 1 layer.

2. A method for preparing an iron / carbon multilayer film, characterized in that, Comprises: By using the magnetron sputtering method, the iron thin film and the carbon thin film are grown alternately to obtain the iron / carbon multilayer film according to claim 1.

3. An electrode material, characterized in that, Comprises the iron / carbon multilayer film according to claim 1.

4. An ion battery, characterized in that, Comprises the electrode material according to claim 3.

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